The invention relates to compositions comprising quaternary ammonium compounds which have a low setting point, good solubility or dispersibility in aqueous media and a low flash point and are thus highly suitable for formulating quaternary ammonium compounds.
Cosmetic compositions, such as, for example, hair-treatment compositions, often comprise sparingly water-soluble quaternary ammonium compounds which have a long-chain alkyl or alkenyl group. Such compositions are usually formulated as aqueous dispersions, emulsions, microemulsions, gels or else in aerosol form and are used, for example, as shampoos, hair cures, hair rinses, etc.
For the manufacturer of such compositions, it is highly advantageous to prepare the quaternary ammonium compounds as compounded materials or formulations in the form of flakes, pellets or pastes which, as well as having a high cationic active ingredient content, have a low setting point and also good solubility or dispersibility in aqueous media.
In accordance with the prior art, the above requirements can be achieved by adding short-chain alcohols, in particular isopropanol, in amounts of from 15 to 20% by weight. Because of their low boiling and flash points, however, such short-chain alcohols are problematical.
As described in WO 00/28950, the short-chain alcohols can be replaced by linear fatty alcohols (e.g. cetyl alcohol, lauryl alcohol, behenyl alcohol or stearyl alcohol). In order to lower the setting point or melting point of the mixtures to temperatures below 100° C., glycols, such as, for example, propylene glycol or 1,3-butanediol, are additionally added. WO 00/28950 further emphasizes that the fatty alcohols are advantageously homogeneous fatty alcohols which contain less than about 10% by weight of another fatty alcohol.